Flexible endoscopes, that is to say endoscopes with a flexible endoscope shaft, are used in medicine and for technical purposes, in order to examine branched or looped regions in the body or to examine machine parts.
Flexible endoscopes differ from rigid endoscopes in that the endoscope shaft of a flexible endoscope can adopt a bent, curved or even looped shape. By virtue of this flexibility of the endoscope shaft, flexible endoscopes are particularly suitable in medicine for operating on and examining regions in the body that have branched or looped structures, for example the gastrointestinal tract or the air passages.
Various approaches to the design of flexible endoscope shafts are known in practice.
DE 199 08 152 A1 discloses an endoscope, in the endoscope shaft of which flexible rods are arranged extending in the longitudinal direction. These flexible rods allow the operator to manually bend the endoscope shaft to a desired curved profile before the operation, such that the endoscope shaft can be advanced to the examination site through an opening in the body. On account of the stiffness of the rods, the endoscope shaft permanently maintains this predefined curved profile during use.
Although this stiffness of the flexion rods, which permit the shaping of the endoscope shaft, ensures an inner stiffness of the endoscope shaft, as is important for the use, it also limits the possible applications of a flexible endoscope of this design, since the predefined curved profile of the endoscope shaft cannot be changed during the operation, for example in order to examine lateral branches or the like.
A flexible endoscope of the type in question is known from EP 1 658 805 B1. In this known flexible endoscope, the endoscope shaft is composed of several shaft portions, which are each formed by a helical spring. The degree of flexibility of the individual shaft portions can be individually adjusted by the choice of different helical springs. The reversibly deformable helical springs of this known endoscope permit a flexible endoscope shaft that can be adjusted in each desired direction even during the examination.
Designing the spring elements of the individual shaft portions as helical springs has the disadvantage that cleaning the narrow helical-spring threads is quite complex. In addition, the production of the different helical springs is very elaborate and cost-intensive.